Unfortunately, Arcane Archer seems to be a sub-class of Fighters accoring to 5e, and it does not seem to be included at all in BG3. q _ q Probably because it apparently belongs to Xanathar's Guide to Everything One can hope it will be included, someday.
A modder discovered assets for a hexblade subclass, possible that it will be in the first expansion/dlc along with other subclasses such as arcane archer. Have hope xanathars sub classes a very popular, so I wouldnt be surprized to see them in before or just after release.